This invention relates to intraocular lenses (IOLs). More particularly, the invention relates to deformable, e.g., foldable, IOLs for placement in eyes, e.g., in the anterior chambers of eyes, and to methods of making and using such IOLs.
The human eye is susceptible to numerous disorders and diseases, a number of which attack the crystalline lens. For example, cataracts mar vision through cloudy or opaque discoloration of the lens of the eye, and can result in partial or complete blindness. When this happens, the crystalline lens can be removed and replaced with an intraocular lens, or IOL. In certain other circumstances, an IOL can be placed in an eye containing the natural crystalline lens, for example, to provide for enhanced vision in the phakic eye. A typical IOL comprises an optic body, or lens, adapted to focus light toward the retina of the eye, and one or more fixation members, or haptics, adapted to at least assist in supporting or fixating the IOL in a suitable location in the eye, such as the anterior chamber, iris, or capsular bag of the eye.
The optic and haptics may be formed as an integral unit from a single material, but in recent years the trend has been toward composite IOLs which use different materials for the various components, so that the properties of these components can be separately optimized. Examples of such composite IOLs are shown in Barrett U.S. Pat. No. 4,997,442 and Vanderbilt U.S. Pat. No. 5,217,491, both of which employ relatively flexible materials in the optic portion and more rigid materials in the haptics. The disclosure of each of these patents is incorporated in its entirety herein by reference. In both the Barrett composite IOL and the Vanderbilt composite IOL, the flexible material of the optic enables the IOL to be deformed, e.g., folded, rolled and the like, for insertion through a small surgical incision in the eye, while the relatively rigid material of the haptics enhances the stability of the optic in the eye.
In most, if not all, prior art composite IOLs, such as those disclosed by Vanderbilt and Barrett, the haptics have been configured as extremely thin, filament or loop-type members suitable for securing the optic in the posterior chamber, or capsular bag, of the eye. The slenderness of these types of fixation members to some degree compensates for the rigidity of the material from which they are made, and enables such fixation members to be curled, folded, or wound up inside a conventional inserter cartridge, without significantly interfering with the folding of the optic. However, such filament or loop type fixation members are generally not recommended for use in the anterior chamber of the eye.
More particularly, anterior chamber IOLs are subject to different conditions than posterior chamber IOLs, and thus differ significantly in their design. For instance, anterior chamber IOLs must be able to withstand the relatively high compressive forces exerted by the surrounding structure of the anterior chamber without allowing significant movement of the optic. In addition, anterior chamber IOLs should be structured to reduce the potential for complications such as pupil ovalling, endothelial cell loss and the like.
Various designs for anterior chamber IOLs are disclosed in Nigam U.S. Pat. No. 5,982,282. Other designs are disclosed in Laguette et al. co-pending U.S. patent application Ser. No. 09/908,515, Nguyen et al. co-pending U.S. patent application Ser. No. 09/847,957, Laguette co-pending U.S. patent application Ser. No. 09/847,958 and Paul co-pending patent application Ser. No. 10/225,990. Each of these co-pending applications and the present application are commonly owned. The disclosure of each of the Nigam patent and the above co-pending U.S. patent applications is hereby incorporated in its entirety by reference herein.
Although the anterior chamber IOLs disclosed in the above patent applications perform satisfactorily in most respects, they all include relatively large fixation members which, if made entirely of rigid material such as poly methylmethacrylate (PMMA), might interfere with the ability of the IOLs to be deformed for insertion into eyes through small incisions. It is advantageous to insert in an IOL though such a small incision to obtain benefits, for example, reduced surgical trauma, reduced recovery time and the like.
Accordingly, it would be advantageous to provide foldable IOLs, for example, anterior chamber IOLs, with fixation members having sufficient rigidity to maintain optic stability in the eye, while still being flexible or deformable enough to allow the IOL to be folded or otherwise deformed for insertion through a small, or even a very small, incision in the eye. In addition, it would be advantageous to provide such IOLs with configurations that are compatible for use with conventional insertion apparatus. It would also be advantageous to devise methods of manufacturing such IOLs that are relatively simple and cost-effective.